Electrical switch blade and terminals

ABSTRACT

A movable switch blade for an electrical switch provided with an external terminal outside the switch and an internal terminal inside the switch for attaching a wire lead.

United States Patent 1191 Wilkinson et al.

ELECTRICAL SWITCH BLADE A TERMINALS Inventors: Richard W. Wilkinson; Jack B. Levy, both of Indianapolis, Ind.

Assignee: P.R. Mallory & Co., Inc.,

Indianapolis, Ind.

Filed: May 12, 1972 Appl. No.: 252,921

use], ..200/284, 339/276 Int. 01. H0lh l/58 Field of Search 200/166 CT, 166 J, 166 31-1;

339/166 R, 170, 63 M, 195 R, 276 R References Cited UNITED STATES PATENTS 8/1968 Prifogle et al 339/195 R 1451 Apr. 16, 1974 3,268,847 8/1966 Klumpp, Jrf 339/166 R 3,665,373 5/1972 Voglesonger 200/166 CT X 3,652,811 3/1972 Barney 200/166 CT X 2,678,429 5/1954 Abbott 200/166 CT 3,182,158 5/1965 Beardow et al.. 200/166 I X 3,175,066 3/1965 Fiddler 200/166 J X 3,051,809 8/1962 Dell 200/166 CT X Primary Examiner-James R. Scott Assistant Examiner--William J. Smith Attorney, Agent, or Firm-Richard H. Childress; Charles W. Hoffmann; Robert F. Meyer [5 7] ABSTRACT A movable switch blade for an electrical switch provided with an external terminal outside the switch andan internal terminal inside the switch for attaching a wire lead.

3 Claims, 4 Drawing Figures ELECTRICAL SWITCH BLADE AND TERMINALS This invention relates to a movable switch blade inside of a switch housing. More particularly, it relates to the type of movable switch blade found in time sequence mechanisms wherein a cam is driven by a synchronous motor to provide an electrical switching program.

Previous ways of attaching a wire lead to a movable blade have been achieved by means of welding an electrical lead wire to the movable switch blade in an area near the supporting portion of the switch blade. This particular design has created a great deal of problems in that oxidation takes place in the welding process thereby distorting the switch blade and/or the electrical lead wire. If the electrical wire is not positioned into a fixture for welding, there may be some variation in the location point when attaching the wire lead to the movable switch blade. Another problem realized when attaching the electrical lead wire to the movable switch blade by means of welding is that a great deal of heat can be generated in this process, which will remove the spring tension in the switch blade, and thereby change the spring characteristics of the switch blade. When the lead wire is attached directly to the movable switch blade in the area where the blade is flexing the mere addition of more material in that area will stiffen the spring and cause the spring to become relatively sluggis h.

Furthermore, if a braided wire lead is used it is possible that all the wire strands in the lead wire would not be welded to the switch blade, thereby causing the possibility of a loose strand in the terminal area to possibly short out other electrical switch blades.

The present invention is therefore concerned with providing a movable switch blade with good flexing characteristics and with terminating means integral with the movable switch blade but in an area remote from the movement of the switch blade.

It is an object of the present invention to provide a switch blade that can be easily formed from a flat strip of metal and can be formed by machinery readily available in the industry.

Another object is to provide a switch blade with good electrical and mechanical terminating characteristics.

Still another object of the present invention is to provide a terminal connection between the switch blade and a lead wire that will allow either manual or automated assembly.

A further object of the present invention is to provide a means of securing the lead wire to the switch blade without destroying or deteriorating the lead wire.

Still another object of the present invention is to attach the lead wire to the switch blade without deforrn-' ing or hampering the spring characteristics of the switch blade.

It is another object of the present invention to provide a method of terminating a wire to a movable switch blade in a compact and tight area.

Another object is to provide an electrical switch blade made from an electrically conductive strip, that has been folded to provide a pair of legs, with one of the legs carrying a contact and a second leg formed to hold an electrical lead wire with the folded area providing an electrical terminal to the switch blade.

A further object of the instant invention is to provide a means of attaching a electrical lead wire that is substantially barrel shaped.

Still another object is to provide a electrical switch blade having a flexible contact blade at one end, a terminal near the opposite end and a crimp terminal for attaching a lead wire, intermediate the two ends. It is a further object of the present invention to provide a movable switch blade that is clean and neat and clear of clutter on the exterior surfaces which could catch and snag on assembly equipment and other associated parts.

These and other objects will become more apparent from the following description and accompanying drawings wherein:

FIG. 1 is a front elevation of a timer switch incorporating the electrical switch blade with portions of its housing broken away.

FIG. 2 is a cross section taken along 22 of FIG. 1;

FIG. 3 is a perspective view of the preassembled switch blade;

FIG. 4 is a prespective view of the switch blade after the lead wire has been crimped in the terminal.

Generally speaking, the objects of the present invention are accomplished by providing an electrical switch blade formed from an electrically conductive strip which has been folded to provide first and second legs with the first leg providing a movable contact blade; and the second leg providing a first electrical terminating means; wherein the electrical switch blade can be mounted in a switch housing with the folded portion of the strip extending outside the switch housing to thereby provide an external electrical terminating means. The electrical switch blade, as illustrated, is mounted in a switch housing which has located in its interior a drive cam, a gear attached to the drive cam with the gear being driven by a synchronous timer motor located outside of the switch housing. To assure proper termination to the electrical switch from external means, the timer motor lead wires are brought into the timer housing so that they may be connected to switch blades and external terminating means. Switch blades are supported in the timer wall intermediate their ends to thereby provide one end of the switch blade with a movable contact and the other end of the switch blade with an external terminal. The switch blades are made of an electrically conductive material with inherent spring characteristics such as a copper brass alloy. The conductive material is in the form of a metal strip which is folded against itself to provide a double thickness at one end of the switch, to thereby provide proper thickness for an external terminal. The fold is made at a point intermediate the two ends of the strip so as to provide one leg of the strip of greater length than the other leg. The longest leg of this strip is then utilized for the movable contact blade and may have located at its extremity an electrical contact.

The second leg has located at its distal end a U- shaped cradle for receiving a lead wire. The U-shaped cradle is rolled and crimped over the lead wire after the lead wire has been inserted into it. The insertion of the lead wire in the cradle and the crimping may take place in an area remote from the timer switch to further aid in attaching the lead wire to the switch blade.

Referring now to the drawings and more specifically to FIG. 1, the present invention is incorporated in an electrical time switch including a housing 12. The housing 12 is formed by a cup-shaped shell 14 and enclosed by a cover 16. The cup-shaped housing 14 has an upstanding wall 18 to provide a terminal station 20. Mounted on the cover 16 and operating through the cover is a synchronous timer motor 22. Electrical leads 24 and 26 of the motor 22 extend through an aperture 28, in the cover 16, and into the interior of the timer housing 12. The timer motor drives a gear 30 which is coupled for rotational movement to a program cam 32 to actuate a plurality of switch blades 34 & 34. Switch blades 34 are supported in the terminal station 20 and extend through the timer housing to provide external electrical terminal means 36. The switch blades 34 are restrained from movement within the terminal station 20 by semi-perforated portions 38 which register in windows 40 along one side of the slots 42 in the terminal station 20. Switch blades 34 are restrained from removal from the slots 42 by cover 16.

As shown in FIGS. 3 and 4 the electrical switch blade 34' is formed from an electrically conductive strip 44. The strip 44 is folded intermediate its distal ends as indicated at 46 to provide a double thickness of material in the area 48. The area 48 near the fold 46 provides an external terminating means 36'. The strip 44 is folded so that a first leg 50 is of greater length than the second leg 52 to provide a movable contact blade 35. The first leg 50 has located near its distal end an electrical contact 54. Second leg 52 has formed near its distal end 56 an internal terminal means 57. Internal terminal means 57 originates with a substantially U-shaped cradle 58, near distal end 56 of leg 52. As seen in FIG. 3, electrical lead wire 24 is placed into the U-shaped cradle 58. Then a forming tool, (not shown) is applied to the free end 60 to roll the free end 60 around the lead wire 24, to thereby form a substantially barrell shaped terminal. An optional crimping action to secure the lead wire 24 to distal end 60 is added by crimping the material at points 61, along the area of the distal end 60. This is done to insure good mechanical contact between the internal terminal means 57 and the lead wire 24. Crimping can be achieved by the previously mentioned forming tool or it may be a seperate operation.

After the lead wire 24 has been crimped into the internal terminating means 57 of the switch blade 34', it is then inserted into the timer switch housing wall 18. Switch blade 34 is placed into slot 42 with its locating dimple 38 trapped in a window 40' to eliminate withdrawal of the switch blade 34'.

Switch blades 34 are formed in substantially the same manner as is switch blade 34 with the deletion of the internal terminating means 57. Terminal 37 is also fonned in the same manner as 34' to provide an external terminating means 36" and an internal terminating means 57' but with the elimination of the movable contact blade 35.

The present invention provides a movable switch blade with a plurality of electrical terminating features which are provided in an area remote from the movable switch blade member thereby eliminating any interference or change of characteristics in the movable switch blade.

What is claimed is:

l. A combination contact blade and electrical terminal means comprising:

a. a strip of electrically conductive material, said strip folded to provide a folded portion and first and second legs, one of said legs being substantially longer than the other to provide said electrical contact blade,

b. at least one electrical contact carried at a distal end of said electrical contact blade,

c. means receiving at least one electrical lead wire at a distal end of said other leg, and

d. an electrical terminal means comprising said folded portion.

2. A combination according to claim 1 wherein said receiving means is a U-shaped cradle.

3. A combination according to claim 1 wherein said receiving means is substantially barrel shaped. 

1. A combination contact blade and electrical terminal means comprising: a. a strip of electrically conductive material, said strip folded to provide a folded portion and first and second legs, one of said legs being substantially longer than the other to provide said electrical contact blade, b. at least one electrical contact carried at a distal end of said electrical contact blade, c. means receiving at least one electrical lead wire at a distal end of said other leg, and d. an electrical terminal means comprising said folded portion.
 2. A combination according to claim 1 wherein said receiving means is a U-shaped cradle.
 3. A combination according to claim 1 wherein said receiving means is substantially barrel shaped. 